Viscosimeter



Jan. 21,1936.

H. T. BOOTH VISGOSIMETER Filed Feb- 71953 INVENTOR lll ATTORNEYS Patented Jan. 21, 1936V PATENT ol-rlcE vrscoslMErEn Harry '1'. Booth, Detroit, Mich., assignor to Lnbrication Control Corporation, Chicago, Ill., a corporation of Delaware Application February v, '1933, serial No. 655.580 11 claim.. (ci. 265-11) This invention relatesto viscosimeters and has for an object a simple and eflicient device for measuring and registering the viscosity of fluid owing through the device.

In a viscosimeter embodying. the invention, fluid is caused to pass successively through two ports, one port vcomprising a friction tube, the resistance vof which to flow varies with the viscosity of the fluid and the other port comprising an orice, theresistance of which to uid flow vis substantially independent of the fluid viscosity, these ports being arranged in either of two orders of succession. Means are provided for regulating the pressure of the uid supplied to the first port to maintain constant pressure in the fluid between the two ports and the pressure of the iiuid supplied to the inlet port is applied to a pressure actuated viscosity indicator. The pressure of the fluid supplied to the inlet port is a function of the viscosity of the fluid and the indicator is suitably calibrated to give direct viscosity readings. A

Other objects, novel features andadvantages of this invention will be apparent from the following specic'ation and accompanying drawing, wherein: I

Fig. 1 is a side elevation of an automobile engine having a lubricating system provided with a viscosimete'r embodying the invention;

Figs. 2 and 3 are vertical central sectional views through a viscosimeter embodying the invention, and f Fig. 4 is a section on the line 4-4 of Fig. 2.

The internal combustion engine III is provided with an oil pan II from the bottom portion of which a pipe I2 leads to the inlet port of a pump I3.; A pipe I4 leads from the outlet port of the pump to the engine bearings (not shown). A pipe I5 leads from pipe I4 to a casing I6 arranged in the upper portion of the oil pan II. A relief valve may be connected to' the pipe I4 to prevent the oil pressure from' exceeding a predetermined maximum.

A hollow piston I'I is slidably mounted in the casing I 6 and is provided with radial ports I 8 and I9 which communicate with peripheral grooves and 2| in the outer surface of the piston (Fig. 4). 'I'he 'position of this piston with respect to the pipe I5 controls ow of oil through said pipe` into the interior of the piston. The piston` is provided with a friction tube 22 which extends through the right end wall of the piston. A spring 23 is interposed between the piston II and a hollow plug 24 mounted in the left end of the casing. An orice 25 in the right hand end of the casing I6 provides for escape of oil from the space between the piston I1 and the right hand end of the casing. The rate of ow through the orice and friction tube is the same. A conduit 26 has one end in communication with the groove through the pipe I5. The resistance of the fric- 2I and has its other `end in communication with the pipe 21 leading to a pressure actuated indicator 28 suitably calibrated to give direct viscosity readings. Y

The friction tube 22 isfof such dimensions that 5 its resistance to uid flow varies with the fluid viscosity, while the orice 25 is of such dimensions that its resistance to' iiuid flow is substantially independent of the uid viscosity and, as will later be described, the pressure of the oil supplied to the friction tube is regulated to maintain substantially constant pressure in'the oil between the friction tube 22 and oriiice'25 independent of the pressure in the uid flowing tion tube to uid flow and the pressure differential across it vary conjointlywith the uid viscosity and as the fluid pressure between the friction tube and orice is maintained constant, and the resistance to ow of the orifice is dependent on the rate of flow and is substantially independent of viscosity, and as the rate of flow through the friction tube and orice is the same, the pressure of the oil supplied to the friction tube is a measure of the rate of iiow through the friction tube and is a function of the oil viscosity. The indicator 28 registers the pressure of the supplied oil and as it is suitably calibrated it gives direct readings of the oil viscosity.

Substantially constant pressure ismaintained 30 in the oil between the friction tube and orifice by regulatory movement of the piston I1 against and under the influence of the spring 23. When the pressure in the space between the friction tube and orifice tends to exceed the strength of the spring 23, the piston II is moved to the left,

thereby reducing the flow of oil into the piston with a corresponding pressure decrease. As the pressure tends to decrease below the strength of. the spring, the piston is moved to the right, thus increasing the oil now and such movement of the piston maintains substantially constant pressure of the oil between the friction tube and orifice.

`The pressure of the oil supplied to the friction tube 1s applied to the indicator '2s through the 45 port I9, conduit 26 and pipe 21. In theevent of a pressure increase in the pipe `I5 without change of viscosity,4 the pressure in the piston I 'I will tend to increase. Such pressure increase results in a pressure increase between the orifice and the friction tube which immediately causes movement of the piston I1 to the left thereby reducing the rate of ow into the piston until the ratio of ilow into the piston and through the outlet port becomes` such that the desired pressure is ob-` tained between the orifice and friction tube. During such adjustment period, the gauge 24 may give a temporary erroneous reading, but such reading will be immediately corrected by reductlonofaowintothoplston lliomolntainuiow predetermined frequency between the orifice and the friction tube. i

The viscosimeter disclosed in Fig. 3 differs from the viscosimeterdisclosed in Fig. 2 in that the piston I1 is provided in' its right end wall with an orice 25 anda friction tube 22 is provided for discharging oil from the space between the piston I1 and the right end of the casing I6. The pressure of the oil in the space between the piston I1 and the right end of the casing I6 is maintained substantially constant by the regulatory action of the piston I1.

As the resistance of the friction tube 22 to fluid flow varies with thel uid viscosity and as vthe uid pressure between the orifice and the friction tube is maintained substantially constant, the rate of fiow through the friction tube varies with viscosity. As the resistance to ow of the orifice is substantially independent of viscosity and Ais dependent upon rate of' fiow and as the rate of flow through the orifice is the same as through the friction tube, the pressure of the oil Asupplied to the friction tube is a measure of the rate of flow and is a function of the oil viscosity. The pressure of the supplied oil is applied to the viscosity indicator 28 as previously described, thus making available'direct viscosity readings. In the modification disclosed in Fig. 2 an increase of pressure within the piston I1 is indicative of increase of viscosity, while in the modification disclosed .in Fig. 3 an increase in pressure within the piston I1 is indicative of decrease of viscosity and the reverse is true for both these modifications.

It is of course understood that various modifications may be made in the device above described without in any way departing from the spirit of the invention as' defined in the appended claims.

I claim:

1. In a viscosimeter having in series a port comprising a friction tube and a second port comprising an orifice, means for supplying uid under pressure to one port, means for regulating the pressure of the supplied uid to maintain conindicator responsive to the fluid pressure immediately in advance of said first port.

2. In a viscosimeter, achamber having an inlet port comprising a friction tube and an outlet port comprising an orifice, means for supplying uid under pressure to said inlet port, means for regulating the pressure of the supplied fluid to maintain constant pressure within said chamber, and a viscosity indicator responsive to the uid pressure immediately in advance of said first port.

3. In a viscosimeter having in series a port comprising a friction tube and a second port comprising an orifice, means for supplying fluid under pressure to said friction tube, means for regulating the pressure of the supplied uid to maintain constant pressure between said ports, and a viscosity indicator responsive to the fiuid pressure immediately in advance of said first port.

4. In a viscosimeter, a chamber having an inlet port comprising an orifice and an outlet port comprising a friction tube,lmeans for supplying -fluid under pressure to said' inlet port, means for aoaaies 5. In a viscosimeter having in series ports comprising an orifice and a friction tube, means 4for supplying uid under pressure to said orifice, means for regulating the pressure of the supplied fluid to maintain constant pressure between said 5 ports, and a viscosity indicator responsive to the fiuid .pressure immediately in advance of said orifice.

6. In a viscosimeter, a casing, a hollow piston mounted in said casing, a spring opposing movement of the piston in one direction, said casing and hollow piston having cooperating ports to control fiuid flow into the piston, a friction tube extending through the end of said hollow piston, said casing having an outlet orifice, and a pressure actuated viscosity indicator connecting with the interior of said piston.

'7. In a viscosimeter, a casing, a hollow piston mounted in said casing, a spring opposing movement of the piston in one direction, said casing 20 and hollow piston having cooperating ports to control fluidow into the piston, said hollow piston having an orifice in one end, a friction tube outlet from said casing, and a pressure actuated viscosity indicator communicating with the inte- 25 rior'of said piston.

8. In a viscosimeter, a casing, a hollow piston mounted in said casing, a spring opposing movement of the piston in one direction, said casing and hollow piston having cooperating ports to 30 control flow into the piston, said hollow piston having an inlet port in one end for flowing fluid into said casing, said casing having an outlet port, and a pressure actuated viscosity indicator connected with the interior of said piston, one of 35 said two last-named ports comprising an orifice and the other comprising a friction tube.

9. In a device of the character described, a chamber having inlet and outlet ports, one of said ports comprising a. friction tube and the other 40 port comprising an orifice, a source of fluid under pressure, means for supplying fluid from said source to the inlet port of said chamber, means responsive solely to the pressure within said chamber for controlling ow from said source 4:, to the inlet port of said chamber to maintain constant pressure within said chamber, and pressure responsive means acted upon by fluid pressure immediately in advance of said first port.

10. Ina device of the 'character described, a chamber having an inlet port comprising a friction tube and anoutlet port comprising an orice, a source of fiuid under pressure, means for supplying uid from said source to said inlet port, means responsive solely to the pressure within said chamber for controlling flow from said source to said inlet port to maintain constant pressure within said chamber, and pressure responsive means acted upon by the supplied fluid immediately in advance of said inlet port.

11. In a device of the character described, a chamber having an inlet'port comprising an orifice and an outlet port comprising a friction tube, a source of uid under pressure, means for supplying fluid from said source to y `said orifice,

means responsive solely to the pressure within said chamber for controlling flow from said source to said orifice to `maintain constant pressure within said chamber, and pressure responsive means acted upon by :fluid pressure immediately in advance of said orice.

HARRY T. BOOTH. 

